Over-Mould The Covering Material Used Is A Flexible Resin

A, two-color mold: two kinds of plastic materials in the same injection molding machine injection molding, two molding, but the product is only a mold once. Generally this molding process is also called double injection molding, usually by a set of molds, and the need for special two-color injection molding machine.

B, plastic mold (Over-Mould): two kinds of plastic materials are not necessarily in the same injection molding machine injection molding, two molding; product from a mold out of the mold, and then into another set of molds The second injection molding. Therefore, the general molding process is usually completed by two sets of molds, without the need for special two-color injection molding machine.

Over-Mould mold in the design should pay attention to the positioning of hard plastic parts, to be a reliable sealant and plastic parts in the anti-skew hole, to prevent the plastic deformation.

Two-color molds are increasingly popular on the market today, in this process can make the appearance of the product more beautiful, easy to change the color and can not spray, but the cost is expensive, high technical requirements.

Over-Mould technology In the past 10 years, the Over-Mould technology has completely changed the aesthetic standards of consumer goods, design ideas and functional requirements. Medical device manufacturers also recognize the potential advantages of the technology and continue to expand its use in the medical field. Secondary injection technology is known for creating "soft surfaces", but it also has many other features, such as ergonomic design, two-color appearance, brand identity and feature improvements. With this technology, you can increase the functionality of the product (eg noise reduction, shock absorption, water resistance, crash) and added value. Over-Mould and injection molding, double injection molding and sandwich injection, are all multi-material injection molding technology. The basic idea of multi-material injection molding is to combine two or more different materials to improve product value. In this context, the first injection material is called a substrate or a base material, and the second injection material is referred to as a cover material. Various Over-Mould technology.

During the Over-Mould, the covering material is injected into the top, bottom, around or inside of the substrate, and is combined into a complete part. This process can be done by multiple injection or insert molding. The commonly used cover material is a resilient resin.

Multiple injection: If the construction of the covering material allows, multiple injection molding is a good method of medical device processing. The technology requires a special injection molding machine with multiple barrels to inject different resins into an injection mold. The barrel should be placed side by side or L-type, by one or more injection points will be injected into the mold. When using the same injection point, called composite, the production of composite parts for the outer coating of the core resin material. The use of multiple injection points, known as the second injection, a material in another material above the molding, resulting in multi-layer structure. But multiple injection molding does not apply to all products. In the case of Over-Mould, it is necessary to move the slider or move the die to another mold cavity. Another way is to feed the core into another injection molding machine.

Inserted Injection Molding: To produce a fully covered injection molded handle, you need to use an insert injection. In order to achieve full coverage, the substrate must be removed from the original cavity and placed into another die and mold cavity for injection of the covering material. In this process, the other mold should be in the same or another different size of the injection molding machine (depending on the size of the injection molding) on the operation. Often the substrate is much larger than the covering material and may require preheating so that the surface temperature is close to the melting point of the covering material to obtain the optimum adhesive strength.

In-mold assembly. Secondary injection is sometimes referred to as in-mold assembly, since the two materials are finally combined together, not just a layered structure, whether it is a separate component or a component material. Whatever the application, it is important to ensure that the substrate and covering material meet the required mechanical or chemical bond strength.

Multi-material injection of the note, in general, to strengthen the degree of adhesion, covering the resin resin melting temperature should be the same with the substrate. If the melting temperature of the covering material is too low, the surface of the substrate can not be melted, and the bonding between the two is not strong enough. But the melting temperature is too high, the substrate will soften the deformation, serious, the cover material will penetrate the substrate, resulting in component processing failure. Therefore, the choice of matching materials to ensure good adhesion. In general, the matching material should have similar chemical properties or contain a matching compound. Substrate and covering materials do not match, usually only the formation of mechanical interlocking, rather than chemical bonding.